Trouble in TN, sort of...

[wolf_walker]

I flew out from NC to OK last Saturday morning to retrieve my trusty old 81 Caddy, father had been using it the last couple years while he tinkered on putting the 1.9 in his 82.

I set out, things went ok, gearing in the new gasser trans is pretty decent, cruise control works alright, everythings groovy.
About 50 miles west of Lebanon TN, crawling along in 1st in traffic, I hear TANG, CLACK CLACK CLACK, pull off and shut it down.  Visual shows nothing wrong, fire it up again, curst, and limp up an offramp to a hotel parking lot.  Run it some more, listen more, decide I'm screwed.
Called father and talked it over, decided to drive it around the hotel a little more, and the sound went away.  I says to myself "well darn".

So.  Something got into/broke off in the combustian chamber, and it's a damn miracle it didnt hole a piston or something.  I drove the rest of the 800 or so miles home and didnt miss a beat.  It does have a funny "hop" at idle, it's subtle, but it's there.  Smoke and power are ok pretty much.  Cold starts fine, cold as it is anyway.  About all I can figure is a glowplug tip broke off maybe, but seems like it should have been hard starting or the light should have accted funny, but maybe not.  Till I can get some heat shields here and start pulling stuff and smoke the business end over, I'm going to keep driving it.

Anyone ever had a similier experience/noise?  It made a hell of a racket.
First time a VW diesel has ever let me down(almost).  And I have a lot of miles on them, this little truck is at almost 600K now.  41mpg running 70 on the interstate BTW.

Another note, father said it started running like in the last year, much smoke, no power, he stuck some new injector nozzles in, cleared it right up.  He did not have them pop'd to check pressure though, but it ran alright.  This funny idle it has now goes away with even a slight bit of throttle.  I've felt a diesel do this exact thing somewhere, but I can't remember when/what/where.

Lord I've missed a VW diesel, the Mercedes and BMW were just not the same.

[chrissev]

having taken cylinder heads off of N/A VW diesel engines I can say that they do build up a lot of carbon on the valves, so maybe what happened was a big chunk of carbon broke off, was pulverized in the cylinder, and went out the exhaust in little pieces.  One of the valves could be a bit bent as a result, causing the funny idle you noticed.  Just an idea.

[chrissev]

having taken cylinder heads off of N/A VW diesel engines I can say that they do build up a lot of carbon on the valves, so maybe what happened was a big chunk of carbon broke off, was pulverized in the cylinder, and went out the exhaust in little pieces.  One of the valves could be a bit bent as a result, causing the funny idle you noticed.  Just an idea.

[chrissev]

having taken cylinder heads off of N/A VW diesel engines I can say that they do build up a lot of carbon on the valves, so maybe what happened was a big chunk of carbon broke off, was pulverized in the cylinder, and went out the exhaust in little pieces.  One of the valves could be a bit bent as a result, causing the funny idle you noticed.  Just an idea.

[wolf_walker]

That would make sense.  The last two years or so it's been driven only about 20K miles, and with progresivly worse injectors, much smoke and little power.  Could have been carbon.  I guess a compression test would tell me if anything is leaking...

[chrissev]

That would make sense.  The last two years or so it's been driven only about 20K miles, and with progresivly worse injectors, much smoke and little power.  Could have been carbon.  I guess a compression test would tell me if anything is leaking...

yup, that'll do it.  If you see smoke and no power, expect a lot of carbon build up on the valves.  I once took the head off a 79 rabbit diesel (1.5 N/A) and the valves were so carboned up that I couldn't see the heads of them, just the carbon and jagged edges where the circular valve head should have been.  Took forever to chip it all off.  

PS: sorry about the three messages.  Computer had the dreaded W32Worm, sending messages by itself.  Cleaned it off today.  Now if I could just find the moron who writes these computer viruses  :evil:

[wolf_walker]

Funny it still runs so well on the highway, just that funky idle.  And I think father has the idle speed bumped up to keep the dash from rattling so bad.  

I guess being that it's still running alright the piston and cylinder wall are probibly alright?  I can't imagine carbon hurting the cylinder wall.

[chrissev]

Funny it still runs so well on the highway, just that funky idle.  And I think father has the idle speed bumped up to keep the dash from rattling so bad.  

I guess being that it's still running alright the piston and cylinder wall are probibly alright?  I can't imagine carbon hurting the cylinder wall.

I doubt anything would have happened to the piston or the cylinder walls.  Even when people break their timing belts the pistons are usually dented but OK (though the connecting rods tend to bend a bit).  I'm just guessing about the carbon idea.  The only way you'd know for sure what happened would be to take the head off and have a look.  Or if you don't mind the funky idle and it still runs and drives fine, just leave it alone.

[wolf_walker]

Well, now it periodicaly ceases to bounce slightly at idle, will ocasionaly idle normaly.  It will also hunt for it's idle speed just slightly sometimes.
I swear that sounds like injectors.  I'm really tempted to just order a set and see.

[Patrick]

Try changing the fuel filter first. If the pump is drawing too hard because of a little dirt, you could get that hunt going on the idle.

[wolf_walker]

Fuel filter and lines are new, noticed today one injector body leaking.
I think I should order a set.

Anyone used them from Colorado Biodiesel?  And why do they have three different non-turbo part numbers?
 :?: